Tens of thousands of university lecturers are staginga mass walkout over their pay and pensions. The strike by staff at up to 500 universities and colleges comes after a wave of action this week and last week.

Some of the lecturers are protesting against plans to end final salary pensions for new members of their pension scheme, the Universities Superannuation Scheme. They argue the change would create a two-tier scheme in which new academics would pay the same as their older colleagues, but have a lesser pension.

The lecturers are striking over what they say is a growing sense of insecurity over their jobs and what has been a real-term pay cut over the last two years.

Universities say academics have had a 0.4% pay rise this academic year.

Sally Hunt, general secretary of the University and College Union, which represents lecturers, said changes to pay and pensions had created "real anger" and the strike was a last resort.

"Staff are sick to the back teeth of being told that their pay and pensions need to be cut to pay for an economic crisis created by others," said Hunt.

Professor Keith Burnett, chair of the Universities and Colleges Employers Association, said employers wanted to work with lecturers.

"There is much uncertainty in higher education at present and this course of action will have the potential to cause further difficulties for students and institutions," he said.

The National Union of Students said it stood in solidarity with the lecturers' strike.

It comes as Aston University announced its intention to charge £9,000 tuition fees – the maximum possible – from autumn next year, while Bishop Grosseteste University College Lincoln said it planned to charge £7,500.

Meanwhile, lecturers who teach English to immigrants are protesting against changes to the cost of their classes.

From autumn, the government will only pay for lessons in English for non-native speakers if they are on jobseekers' allowance or employability skills allowance benefits. The government will pay half the cost of the lessons for some others.

Lecturers said some of their pupils would not be able to afford the lessons and this would mean classes would stop in some areas and teachers would be made redundant.

Official figures show universities' endowment income dropped by 39% in 2009-10, compared with the year before.

The fees of international students from outside the European Union made up 9.6% of universities' income last year, compared with 8.7% the year before.